The footage you need is always from the one camera that was pointed somewhere else. Coverage planning costs nothing and decides whether a system is useful.

Every surveillance system gets judged on a single day: the day something happens and someone asks to see the footage. Systems that fail that test usually failed at the planning stage, not the installation.

Decide what each camera is for

A camera can do one of three jobs well, and trying to make one camera do all three is why footage disappoints:

  • Overview — what happened, and in what order
  • Identification — who it was, close enough to recognise a face
  • Detail — a number plate, a serial number, a transaction at a till

An overview camera at the gate will not identify anyone. An identification camera needs to be close, at head height, and pointed where people naturally slow down: doorways, turnstiles, tills.

Work out retention before you size storage

How long do you need to be able to look back? A week is often enough for a shop. An institution investigating something that happened while staff were on leave may need a month. Retention, resolution and camera count together decide storage, and it is far cheaper to decide that up front than to discover in month two that footage is already overwritten.

Plan for the dark and for the power cut

Most incidents happen at night. Check what a camera sees in its own infrared, not in daylight. And put the recorder on backup power — a surveillance system that stops recording during an outage is a surveillance system that misses exactly the events you most wanted recorded.